Balancing equations of chemical reactions

If the equation is already balanced, write “The equation is balanced” right under it in order
to get full credit.

Balance the following chemical equations (3 points each):

9. _____ K(s) + _____ Cl2(g) → _____ KCl(s)

10. _____NaBr(aq) + _____ Cl2(g) → _____ NaCl(aq) + _____ Br2(aq)

11. _____ SiCl4(l) + _____ H2O(l) → _____ SiO2(s) + _____ HCl(aq)

12. ______SnO2(s) + ______ H2(g) → ______ Sn(s) + ______ H2O(g)

13. ______CH4(g) + ______ O2(g) → ______ CO2(g) + ______ H2O(g)

14. ______Na2S(aq) + ______ I2(aq) → ______ NaI(aq) + ______ S(s)

15. _____ CO(g) + _____ H2O(g) → _____ CO2(g) + _____ H2(g)

I'll do one for you

#11.
SiCl4(l) + H2O(l) → SiO2(s) + HCl(aq)
As it stands, the Si atom balance
For Cl, you have 4 on the left, so you need 4 on the right.
SiCl4(l) + H2O(l) → SiO2(s) + 4HCl(aq)
Now the Cl atoms balance, but the O need some adjustment.
SiCl4(l) + 2H2O(l) → SiO2(s) + 4HCl(aq)
Now we have 2 O's on each side, and the 4 H's also balance out.
Done.
Now you try the rest.

9. 2K(s) + Cl2(g) → 2KCl(s)

10. 2NaBr(aq) + Cl2(g) → 2NaCl(aq) + Br2(aq)

11. SiCl4(l) + 2H2O(l) → SiO2(s) + 4HCl(aq)

12. SnO2(s) + 2H2(g) → Sn(s) + 2H2O(g)

13. CH4(g) + 2O2(g) → CO2(g) + 2H2O(g)

14. Na2S(aq) + I2(aq) → 2NaI(aq) + S(s)

15. CO(g) + H2O(g) → CO2(g) + H2(g)

The equation is balanced.

To balance a chemical equation, we need to ensure that the number of atoms of each element is the same on both sides of the equation.

Let's go through each equation step by step:

9. K(s) + Cl2(g) → KCl(s)
To balance this equation, we need the same number of potassium (K) atoms and chlorine (Cl) atoms on both sides.
Since there is only one potassium on the left side, we need one potassium on the right side. So, we write:
K(s) + Cl2(g) → KCl(s)

10. NaBr(aq) + Cl2(g) → NaCl(aq) + Br2(aq)
We start by balancing the sodium (Na) atoms. There is one on each side, so we can move on to the bromine (Br) atoms.
We have one bromine on the left side, which means we need one bromine molecule (Br2) on the right side.
NaBr(aq) + Cl2(g) → NaCl(aq) + Br2(aq)

11. SiCl4(l) + H2O(l) → SiO2(s) + HCl(aq)
Begin by balancing the silicon (Si) atoms. There is one on each side, so we move on to hydrogen (H).
To balance the hydrogen atoms, we need to put a coefficient of 2 in front of HCl(aq) on the right side.
SiCl4(l) + H2O(l) → SiO2(s) + 2HCl(aq)

12. SnO2(s) + H2(g) → Sn(s) + H2O(g)
Start with balancing the tin (Sn) atoms. There is one on each side, so let's focus on oxygen (O) atoms.
On the left side, we have two oxygen atoms, and on the right side, we have one oxygen atom in H2O(g).
To balance the oxygen atoms, we need to put a coefficient of 2 in front of H2O(g) on the right side.
SnO2(s) + H2(g) → Sn(s) + 2H2O(g)

13. CH4(g) + O2(g) → CO2(g) + H2O(g)
Begin by balancing the carbon (C) atoms. There is one on each side, so we move on to hydrogen (H) atoms.
On the left side, we have four hydrogen atoms, and on the right side, we have two in H2O(g).
To balance the hydrogen atoms, we need to put a coefficient of 2 in front of H2O(g) on the right side.
CH4(g) + O2(g) → CO2(g) + 2H2O(g)

14. Na2S(aq) + I2(aq) → NaI(aq) + S(s)
Start with balancing the sodium (Na) atoms. There are two on the left side, so we need two on the right side.
Na2S(aq) + I2(aq) → 2NaI(aq) + S(s)

15. CO(g) + H2O(g) → CO2(g) + H2(g)
Begin by balancing the carbon (C) atoms. There is one on each side, so we move on to hydrogen (H) atoms.
On the left side, we have two hydrogen atoms, and on the right side, we have two in H2(g).
The equation is already balanced:
CO(g) + H2O(g) → CO2(g) + H2(g) (The equation is balanced)